Set connection state to not connected while ACL is lost

Device connection state should represent actual connection state of ACL.
When state is not set on ACL connection/disconnection it may lead to
invalid state representation when checking.

Tag: #feature
Bug: 234312519
Test: atest bt_host_test_bta
Change-Id: I61cd3594ee4f4512236a8597789bcd735c50a975